41 CFR § 51-5.3 - Scope of requirement.
(a) When a commodity is included on the Procurement List, the mandatory source requirement covers the National Stock Number or item designation listed and commodities that are essentially the same as the listed item. In some instances, only a portion of the Government requirement for a National Stock Number or item designation is specified by the Procurement List. Where geographic areas, quantities, percentages or specific supply locations for a commodity are listed, the mandatory provisions of the JWOD Act apply only to the portion or portions of the commodity indicated by the Procurement List.
(b) For services, where an agency and location or geographic area are listed on the Procurement List, only the service for the location or geographic area listed must be procured from the nonprofit agency, except as provided in § 51–6.14 of this chapter. Where no location or geographic area is indicated by the Procurement List, it is mandatory that the total Government requirement for that service be procured from a nonprofit agency.
(c) When a commodity or service is added to the Procurement List, the addition does not affect contracts for the commodity or service awarded prior to the effective date of the Procurement List addition or options exercised under those contracts.